dma-buf.h

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Header file for dma buffer sharing framework.
 *
 * Copyright(C) 2011 Linaro Limited. All rights reserved.
 * Author: Sumit Semwal <sumit.semwal@ti.com>
 *
 * Many thanks to linaro-mm-sig list, and specially
 * Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
 * Daniel Vetter <daniel@ffwll.ch> for their support in creation and
 * refining of this idea.
 */
#ifndef __DMA_BUF_H__
#define __DMA_BUF_H__
 
#include <linux/iosys-map.h>
#include <linux/file.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/list.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
/*
 * DCL delta: mainline's <linux/fs.h> includes <linux/uuid.h> (linux-7.2
 * fs.h:37), and that is how DRM headers that name uuid_t -- virtgpu_drv.h:101
 * is the reader here -- see the type. DCL's fs.h is a pinned ABI blob that
 * includes nothing (see its opening note), so the include its mainline
 * counterpart would have supplied is carried here, on the header that pulls
 * fs.h in: drm_gem.h -> dma-buf.h.
 */
#include <linux/uuid.h>
#include <linux/dma-fence.h>
#include <linux/wait.h>
#include <linux/pci-p2pdma.h>
 
struct device;
struct dma_buf;
struct dma_buf_attachment;
 
struct dma_buf_ops {
    int (*attach)(struct dma_buf *, struct dma_buf_attachment *);
 
    void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
 
    int (*pin)(struct dma_buf_attachment *attach);
 
    void (*unpin)(struct dma_buf_attachment *attach);
 
    struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
                     enum dma_data_direction);
    void (*unmap_dma_buf)(struct dma_buf_attachment *,
                  struct sg_table *,
                  enum dma_data_direction);
 
    /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
     * if the call would block.
     */
 
    void (*release)(struct dma_buf *);
 
    int (*begin_cpu_access)(struct dma_buf *, enum dma_data_direction);
 
    int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
 
    int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
 
    int (*vmap)(struct dma_buf *dmabuf, struct iosys_map *map);
    void (*vunmap)(struct dma_buf *dmabuf, struct iosys_map *map);
};
 
struct dma_buf {
    size_t size;
 
    struct file *file;
 
    struct list_head attachments;
 
    const struct dma_buf_ops *ops;
 
    unsigned vmapping_counter;
 
    struct iosys_map vmap_ptr;
 
    const char *exp_name;
 
    const char *name;
 
    spinlock_t name_lock;
 
    struct module *owner;
 
    struct list_head list_node;
 
    void *priv;
 
    struct dma_resv *resv;
 
    wait_queue_head_t poll;
 
    struct dma_buf_poll_cb_t {
        struct dma_fence_cb cb;
        wait_queue_head_t *poll;
 
        __poll_t active;
    } cb_in, cb_out;
};
 
struct dma_buf_attach_ops {
    bool allow_peer2peer;
 
    void (*invalidate_mappings)(struct dma_buf_attachment *attach);
};
 
struct dma_buf_attachment {
    struct dma_buf *dmabuf;
    struct device *dev;
    struct list_head node;
    bool peer2peer;
    const struct dma_buf_attach_ops *importer_ops;
    void *importer_priv;
    void *priv;
};
 
struct dma_buf_export_info {
    const char *exp_name;
    struct module *owner;
    const struct dma_buf_ops *ops;
    size_t size;
    int flags;
    struct dma_resv *resv;
    void *priv;
};
 
#define DEFINE_DMA_BUF_EXPORT_INFO(name)    \
    struct dma_buf_export_info name = { .exp_name = KBUILD_MODNAME, \
                     .owner = THIS_MODULE }
 
static inline void get_dma_buf(struct dma_buf *dmabuf)
{
    get_file(dmabuf->file);
}
 
static inline bool dma_buf_is_dynamic(struct dma_buf *dmabuf)
{
    return !!dmabuf->ops->pin;
}
 
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
                      struct device *dev);
struct dma_buf_attachment *
dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev,
               const struct dma_buf_attach_ops *importer_ops,
               void *importer_priv);
void dma_buf_detach(struct dma_buf *dmabuf,
            struct dma_buf_attachment *attach);
int dma_buf_pin(struct dma_buf_attachment *attach);
void dma_buf_unpin(struct dma_buf_attachment *attach);
 
struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);
 
int dma_buf_fd(struct dma_buf *dmabuf, int flags);
struct dma_buf *dma_buf_get(int fd);
void dma_buf_put(struct dma_buf *dmabuf);
 
struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *,
                    enum dma_data_direction);
void dma_buf_unmap_attachment(struct dma_buf_attachment *, struct sg_table *,
                enum dma_data_direction);
void dma_buf_invalidate_mappings(struct dma_buf *dma_buf);
bool dma_buf_attach_revocable(struct dma_buf_attachment *attach);
int dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
                 enum dma_data_direction dir);
int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
               enum dma_data_direction dir);
struct sg_table *
dma_buf_map_attachment_unlocked(struct dma_buf_attachment *attach,
                enum dma_data_direction direction);
void dma_buf_unmap_attachment_unlocked(struct dma_buf_attachment *attach,
                       struct sg_table *sg_table,
                       enum dma_data_direction direction);
 
int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
         unsigned long);
int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map);
void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map);
int dma_buf_vmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map);
void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map);
struct dma_buf *dma_buf_iter_begin(void);
struct dma_buf *dma_buf_iter_next(struct dma_buf *dmbuf);
#endif /* __DMA_BUF_H__ */